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        // 打车起步价13（2公里），之后每公里5元。输入公里数计算打车价格
        // 如果有堵车，多加10元拥堵费
        var car = (function () {
          var start = 13; //起步价
          var total = 0; //总价
          return {
            price: function (n) {
              if (n <= 3) {
                total = start;
              } else {
                total = start + (n - 3) * 5;
              }
              return total;
            },
            yd: function (flag) {
              return flag ? total + 10 : total;
            }, //拥堵费用
          };
        })();
        car.price(5);

        console.log(car.price(5));
        console.log(car.yd(true));
      };
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